From 5e12a48c0eead48916b0e16a0f31c5e92e71925b Mon Sep 17 00:00:00 2001
From: mhsdesign <85400359+mhsdesign@users.noreply.github.com>
Date: Mon, 28 Oct 2024 12:51:49 +0100
Subject: [PATCH] TASK: Turn full discard also into a no-op if there are no
 changes

---
 .../02-DiscardWorkspace.feature               | 23 +++++++++++++++++++
 .../Feature/WorkspaceCommandHandler.php       |  7 ++++--
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/Neos.ContentRepository.BehavioralTests/Tests/Behavior/Features/W9-WorkspaceDiscarding/02-DiscardWorkspace.feature b/Neos.ContentRepository.BehavioralTests/Tests/Behavior/Features/W9-WorkspaceDiscarding/02-DiscardWorkspace.feature
index 27cc51b7e0b..0e180f7d0dd 100644
--- a/Neos.ContentRepository.BehavioralTests/Tests/Behavior/Features/W9-WorkspaceDiscarding/02-DiscardWorkspace.feature
+++ b/Neos.ContentRepository.BehavioralTests/Tests/Behavior/Features/W9-WorkspaceDiscarding/02-DiscardWorkspace.feature
@@ -150,3 +150,26 @@ Feature: Workspace discarding - basic functionality
       | newContentStreamId | "user-cs-two-discarded" |
 
     Then workspaces live,user-ws-one,user-ws-two have status UP_TO_DATE
+
+  Scenario: Discard is a no-op if there are no changes (and the workspace is outdated)
+    And the command SetNodeProperties is executed with payload:
+      | Key                       | Value                                  |
+      | workspaceName             | "live"                                 |
+      | nodeAggregateId           | "nody-mc-nodeface"                     |
+      | originDimensionSpacePoint | {}                                     |
+      | propertyValues            | {"text": "Modified in live workspace"} |
+
+    And the command DiscardWorkspace is executed with payload:
+      | Key                | Value                   |
+      | workspaceName      | "user-test"             |
+      | newContentStreamId | "user-cs-two-discarded" |
+    Then workspaces user-test has status OUTDATED
+
+    Then I expect exactly 1 events to be published on stream with prefix "Workspace:user-test"
+
+    And I am in workspace "user-test" and dimension space point {}
+    Then I expect node aggregate identifier "nody-mc-nodeface" to lead to node user-cs-identifier;nody-mc-nodeface;{}
+    And I expect this node to have the following properties:
+      | Key  | Value      |
+      | text | "Original" |
+    Then I expect the content stream "user-cs-two-discarded" to not exist
diff --git a/Neos.ContentRepository.Core/Classes/Feature/WorkspaceCommandHandler.php b/Neos.ContentRepository.Core/Classes/Feature/WorkspaceCommandHandler.php
index 34293ff53ef..0cea05dc7e3 100644
--- a/Neos.ContentRepository.Core/Classes/Feature/WorkspaceCommandHandler.php
+++ b/Neos.ContentRepository.Core/Classes/Feature/WorkspaceCommandHandler.php
@@ -685,7 +685,11 @@ private function handleDiscardWorkspace(
         $workspace = $this->requireWorkspace($command->workspaceName, $commandHandlingDependencies);
         $baseWorkspace = $this->requireBaseWorkspace($workspace, $commandHandlingDependencies);
 
-        return $this->discardWorkspace(
+        if (!$this->hasEventsInContentStreamExceptForking(ContentStreamEventStreamName::fromContentStreamId($workspace->currentContentStreamId))) {
+            return;
+        }
+
+        yield from $this->discardWorkspace(
             $workspace,
             $baseWorkspace,
             $command->newContentStreamId,
@@ -706,7 +710,6 @@ private function discardWorkspace(
         ContentStreamId $newContentStream,
         CommandHandlingDependencies $commandHandlingDependencies
     ): \Generator {
-        // todo only discard if changes, needs new changes flag on the Workspace model
         yield $this->forkContentStream(
             $newContentStream,
             $baseWorkspace->currentContentStreamId,